Buggy code:
public abstract class AbstractPatternNodeVisitor implements PatternNodeVisitor { public Object visit ( AnyTypePattern node , Object data ) { } public Object visit ( NoTypePattern node , Object data ) { } public Object visit ( EllipsisTypePattern node , Object data ) { } public Object visit ( AnyWithAnnotationTypePattern node , Object data ) { } public Object visit ( AnyAnnotationTypePattern node , Object data ) { } public Object visit ( EllipsisAnnotationTypePattern node , Object data ) { } public Object visit ( AndAnnotationTypePattern node , Object data ) { } public Object visit ( AndPointcut node , Object data ) { } public Object visit ( AndTypePattern node , Object data ) { } public Object visit ( AnnotationPatternList node , Object data ) { } public Object visit ( AnnotationPointcut node , Object data ) { } public Object visit ( ArgsAnnotationPointcut node , Object data ) { } public Object visit ( ArgsPointcut node , Object data ) { } public Object visit ( BindingAnnotationTypePattern node , Object data ) { } public Object visit ( BindingTypePattern node , Object data ) { } public Object visit ( CflowPointcut node , Object data ) { } public Object visit ( ConcreteCflowPointcut node , Object data ) { } public Object visit ( DeclareAnnotation node , Object data ) { } public Object visit ( DeclareErrorOrWarning node , Object data ) { } public Object visit ( DeclareParents node , Object data ) { } public Object visit ( DeclarePrecedence node , Object data ) { } public Object visit ( DeclareSoft node , Object data ) { } public Object visit ( ExactAnnotationTypePattern node , Object data ) { } public Object visit ( ExactTypePattern node , Object data ) { } public Object visit ( HandlerPointcut node , Object data ) { } public Object visit ( IfPointcut node , Object data ) { } public Object visit ( KindedPointcut node , Object data ) { } public Object visit ( ModifiersPattern node , Object data ) { } public Object visit ( NamePattern node , Object data ) { } public Object visit ( NotAnnotationTypePattern node , Object data ) { } public Object visit ( NotPointcut node , Object data ) { } public Object visit ( NotTypePattern node , Object data ) { } public Object visit ( OrAnnotationTypePattern node , Object data ) { } public Object visit ( OrPointcut node , Object data ) { } public Object visit ( OrTypePattern node , Object data ) { } public Object visit ( PerCflow node , Object data ) { } public Object visit ( PerFromSuper node , Object data ) { } public Object visit ( PerObject node , Object data ) { } public Object visit ( PerSingleton node , Object data ) { } public Object visit ( PerTypeWithin node , Object data ) { } public Object visit ( PatternNode node , Object data ) { } public Object visit ( ReferencePointcut node , Object data ) { } public Object visit ( SignaturePattern node , Object data ) { } public Object visit ( ThisOrTargetAnnotationPointcut node , Object data ) { } public Object visit ( ThisOrTargetPointcut node , Object data ) { } public Object visit ( ThrowsPattern node , Object data ) { } public Object visit ( TypePatternList node , Object data ) { } public Object visit ( WildAnnotationTypePattern node , Object data ) { } public Object visit ( WildTypePattern node , Object data ) { } public Object visit ( WithinAnnotationPointcut node , Object data ) { } public Object visit ( WithinCodeAnnotationPointcut node , Object data ) { } public Object visit ( WithinPointcut node , Object data ) { } public Object visit ( WithincodePointcut node , Object data ) { } public Object visit ( MatchesNothingPointcut node , Object data ) { } <START_BUG> public Object visit ( TypeVariable node , Object data ) { <END_BUG> return node ; } public Object visit ( TypeVariablePatternList node , Object data ) { } }

Fix:
public Object visit ( TypeVariablePattern node , Object data ) {